The systems and method discussed herein treat tissue in the human body. In a particular variation, systems and methods described below treat cosmetic conditions affecting the skin of various body parts, including face, neck, and other areas traditionally prone to wrinkling, lines, sagging and other distortions of the skin.
Exposure of the skin to environmental forces can, over time, cause the skin to sag, wrinkle, form lines, or develop other undesirable distortions. Even normal contraction of facial and neck muscles, e.g. by frowning or squinting, can also over time form furrows or bands in the face and neck region. These and other effects of the normal aging process can present an aesthetically unpleasing cosmetic appearance.
Accordingly, there is well known demand for cosmetic procedures to reduce the visible effects of such skin distortions. There remains a large demand for “tightening” skin to remove sags and wrinkles especially in the regions of the face and neck.
One method surgically resurfaces facial skin by ablating the outer layer of the skin (from 200 μm to 600 μm), using laser or chemicals. In time, a new skin surface develops. The laser and chemicals used to resurface the skin also irritate or heat the collagen tissue present in the dermis. When irritated or heated in prescribed ways, the collagen tissue partially dissociates and, in doing so, shrinks. The shrinkage of collagen also leads to a desirable “tightened” look. Still, laser or chemical resurfacing leads to prolonged redness of the skin, infection risk, increased or decreased pigmentation, and scarring.
Lax et al. U.S. Pat. No. 5,458,596 describes the use of radio frequency energy to shrink collagen tissue. This cosmetically beneficial effect can be achieved in facial and neck areas of the body in a minimally intrusive manner, without requiring the surgical removal of the outer layers of skin and the attendant problems just listed.
Utely et al. U.S. Pat. No. 6,277,116 also teaches a system for shrinking collagen for cosmetically beneficial purposes by using an electrode array configuration.
However, areas of improvement remain with the previously known systems. In one example, fabrication of an electrode array may cause undesired cross-current paths forming between adjacent electrodes resulting in an increase in the amount of energy applied to tissue.
In another example, when applying the array to tissue, the medical practitioner experiences a “bed-of-nails”. In other words, the number of electrodes and their configuration in the array effectively increases the total surface area of the electrode array. The increase in effective surface area then requires the medical practitioner to apply a greater force to the electrode array in order to penetrate tissue. Such a drawback may create collateral damage as one or more electrode may be placed too far within the skin. Additionally, the patient may experience the excessive force as the medical practitioner increases the applied force to insert the array within tissue.
Thermage, Inc. of Hayward Calif. also holds patents and sells devices for systems for capacitive coupling of electrodes to deliver a controlled amount of radiofrequency energy. This controlled delivery of RF energy creates an electric field that generates “resistive heating” in the skin to produce cosmetic effects while cooling the epidermis to prevent external burning of the epidermis.
In such systems that treat in a non-invasive manner, generation of energy to produce a result at the dermis results in unwanted energy passing to the epidermis. Accordingly, excessive energy production creates the risk of unwanted collateral damage to the skin.
In view of the above, there remains a need for an improved energy delivery system. Such systems may be applied to create improved electrode array delivery system for cosmetic treatment of tissue. In particular, such an electrode array may provide deep uniform heating by applying energy to tissue below the epidermis to causes deep structures in the skin to immediately tighten. Over time, new and remodeled collagen may further produce a tightening of the skin, resulting in a desirable visual appearance at the skin's surface.